Additive manufacturing of thermoplastic polymers (typically nylon) is well known. For example, fused filament fabrication (FFF), which is also commonly called plastic jet printing has been used to form 3d parts by using thermoplastic filaments that are drawn into a nozzle heated, melted and then extruded where the extruded filaments fuse together upon cooling (see, for example, U.S. Pat. No. 5,121,329). Because the technique requires melting of a filament and extrusion, the materials have been limited to thermoplastic polymers (typically nylon) and complex apparatus. In addition, the technique has required support structures that are also extruded when making complex parts that must survive the elevated temperature needed to form the part, while also being easily removed, for example, by dissolving it or releasing it by dissolving a layer between it and the final article such as described by U.S. Pat. No. 5,503,785.
Several polymeric materials that may be used to form support structures that may be dissolved in water have been described such as poly(2-ethyl-2-oxazoline) and impact modified terpolymers of styrene, methacrylic acid and butyl acrylate commercially available under BELLAND 88140 and a copolymer comprised of maleic anhydride such as described in U.S. Pat. No. 5,503,785 and European Patent Applications EP2514775; EP1773560 and EP1194274. U.S. Pat. No. 5,503,785 describes several other polymers that may be used as water soluble release layer for an underlying support structure. Because such polymers are dissolved in water and generally require other additives to function, they present a problem of disposal and recovery for additive manufacturing particularly as these methods become more widely used for production.
It would be desirable to provide a method to address the problem of disposal of polymers in waste streams arising from additive manufacturing such as described above.